.TH GNUNET-DOWNLOAD "1" "31 Jan 2016" "GNUnet"
.SH NAME
gnunet\-download \- a command line interface for downloading files from GNUnet
.SH SYNOPSIS
.B gnunet\-download
[\fIOPTIONS\fR] \-\- GNUNET_URI
.SH DESCRIPTION
.PP
Download files from GNUnet.

.TP
\fB\-a \fILEVEL\fR, \fB\-\-anonymity=LEVEL\fR
set desired level of receiver anonymity.  Default is 1.

.TP
\fB\-c \fIFILENAME\fR, \fB\-\-config=FILENAME\fR
use config file (defaults: ~/.config/gnunet.conf)

.TP
\fB\-D, \fB\-\-delete\-incomplete\fR
causes gnunet\-download to delete incomplete downloads when aborted with
CTRL\-C.  Note that complete files that are part of an incomplete recursive
download will not be deleted even with this option.  Without this option,
terminating gnunet\-download with a signal will cause incomplete
downloads to stay on disk.  If gnunet\-download runs to (normal) completion
finishing the download, this option has no effect.

.TP
\fB\-h\fR, \fB\-\-help\fR
print help page

.TP
\fB\-L \fILOGLEVEL\fR, \fB\-\-loglevel=LOGLEVEL\fR
Change the loglevel.  Possible values for LOGLEVEL are
ERROR, WARNING, INFO and DEBUG.

.TP
\fB\-n\fR, \fB\-\-no-network\fR
Only search locally, do not forward requests to other peers.

.TP
\fB\-o \fIFILENAME\fR, \fB\-\-output=FILENAME\fR
write the file to FILENAME.  Hint: when recursively downloading a directory,
append a '/' to the end of the FILENAME to create a directory of that name.
If no FILENAME is specified, gnunet\-download constructs a temporary ID from
the URI of the file.  The final filename is constructed based on meta\-data
extracted using libextractor (if available).

.TP
\fB\-p \fIDOWNLOADS\fR, \fB\-\-parallelism=DOWNLOADS\fR
set the maximum number of parallel downloads that is allowed.  More parallel
downloads can, to some extent, improve the overall time to download content.
However, parallel downloads also take more memory (see also option \-r which
can be used to limit memory utilization) and more sockets.  This option is
used to limit the number of files that are downloaded in parallel (\-r can
be used to limit the number of blocks that are concurrently requested).
As a result, the value only matters for recursive downloads.
The default value is 32.

.TP
\fB\-r \fIREQUESTS\fR, \fB\-\-request-parallelism=REQUESTS\fR
set the maximum number of parallel requests that is allowed.  If multiple
files are downloaded, gnunet\-download will not run them in parallel if
this would cause the number of pending requests to possibly exceed the
given value.  This is useful since, for example, downloading dozens of
multi\-gigabyte files in parallel could exhaust memory resources and would
hardly improve performance.   Note that the limit only applies to this
specific process and that other download activities by other processes
are not included in this limit.  Consider raising this limit for large
recursive downloads with many large files if memory and network
bandwidth are not fully utilized and if the parallelism limit (\-p option)
is not reached.  This option also only matters for recursive downloads.
The default value is 4092.

.TP
\fB\-R\fR, \fB\-\-recursive\fR
download directories recursively (and in parallel). Note that the URI
must belong to a GNUnet directory and that the filename given to "\-o"
must end in '.gnd' \-\- otherwise, you will receive an error.  You may
want to use "DIRNAME/.gnd" for the filename, this way a directory
"DIRNAME/" will be created, and GNUnet's internal directory
information will be stored in "DIRNAME/.gnd". However, it is also
possible to specify "DIRNAME.gnd", in which case the files from the
directory will end up in "DIRNAME/", while GNUnet's directory meta
data will be in "DIRNAME.gnd".

.TP
\fB\-v\fR, \fB\-\-version\fR
print the version number

.TP
\fB\-V\fR, \fB\-\-verbose\fR
print progress information

.SH NOTES
The GNUNET_URI is typically obtained from
gnunet\-search. gnunet\-fs\-gtk can also be used instead of
gnunet\-download.  If you ever have to abort a download, you can at
any time continue it by re\-issuing gnunet\-download with the same
filename. In that case GNUnet will not download blocks again that are
already present. GNUnet's file\-encoding will ensure file integrity,
even if the existing file was not downloaded from GNUnet in the first
place. Temporary information will be appended to the target file until
the download is completed.

.SH SETTING ANONYMITY LEVEL

The \fB\-a\fR option can be used to specify additional anonymity
constraints. If set to 0, GNUnet will try to download the file as fast
as possible, including using non-anonymous methods.  If you set it to
1 (default), you use the standard anonymous routing algorithm (which
does not explicitly leak your identity).  However, a powerful
adversary may still be able to perform traffic analysis (statistics)
to over time infer data about your identity.  You can gain better
privacy by specifying a higher level of anonymity, which increases the
amount of cover traffic your own traffic will get, at the expense of
performance.  Note that your download performance is not only
determined by your own anonymity level, but also by the anonymity
level of the peers publishing the file.  So even if you download with
anonymity level 0, the peers publishing the data might be sharing with
a higher anonymity level, which in this case will determine
performance.  Also, peers that cache content in the network always use
anonymity level 1.

This option can be used to limit requests further than that. In
particular, you can require GNUnet to receive certain amounts of
traffic from other peers before sending your queries. This way, you
can gain very high levels of anonymity \- at the expense of much more
traffic and much higher latency. So set it only if you really believe
you need it.

The definition of ANONYMITY\-RECEIVE is the following.  0 means no
anonymity is required.  Otherwise a value of 'v' means that 1 out of v
bytes of "anonymous" traffic can be from the local user, leaving 'v-1'
bytes of cover traffic per byte on the wire.  Thus, if GNUnet routes n
bytes of messages from foreign peers (using anonymous routing), it may
originate n/(v-1) bytes of queries in the same time\-period. The
time\-period is twice the average delay that GNUnet defers forwarded
queries.

The default is 1 and this should be fine for most users.  Also notice
that if you choose very large values, you may end up having no
throughput at all, especially if many of your fellow GNUnet\-peers all
do the same.

.SH FILES
.TP
~/.config/gnunet.conf
GNUnet configuration file
.SH "REPORTING BUGS"
Report bugs to <https://gnunet.org/bugs/> or by sending electronic mail to <gnunet\-developers@gnu.org>
.SH "SEE ALSO"
\fBgnunet\-fs\-gtk\fP(1), \fBgnunet\-publish\fP(1), \fBgnunet\-search\fP(1), \fBgnunet.conf\fP(5), \fBgnunet\-service\-fs\fP(1)
